1. Technical Field
The present disclosure relates to a toner supply device for use in image forming apparatuses such as copier, printer, facsimile machine, and multifunctional machines, and an image forming apparatus using the toner supply device.
2. Description of Related Art
In an electrophotographic image forming apparatus, an electrostatic latent image is formed on a photoreceptor and is developed into a toner image with toner particles supplied from a developing device. As the toner particles are consumed, a toner supply device supplies fresh toner particles to the developing device.
A toner supply device which is detachably attachable to an image forming apparatus is known. Upon attachment of a toner supply device to an image forming apparatus, a discharge aperture of the toner supply device is connected with a supply aperture of the developing device so that toner particles are supplied from the toner supply device to the developing device. Upon detachment of the toner supply device from the image forming apparatus, the discharge aperture is disconnected with the supply aperture. To prevent scatter of toner particles from the discharge aperture, the toner supply device may be equipped with a shutter member.
Japanese Patent Application Publication Nos. 2009-86219 and 2009-86220 each describe a toner supply device having a shutter member that is movable. FIG. 1 is a schematic view of a related-art toner supply device. A shutter member 200 is inserted into a casing 300 of a toner supply device through an aperture 600. When the shutter member 200 is in a position shown by two-dot chain lines in FIG. 1, a toner path 400 is closed with the shutter member 200 and toner particles in the casing 300 are prevented from discharging from a discharge aperture 500. When the shutter member 200 is in a position shown by solid lines in FIG. 1, the toner path 400 is opened and toner particles are dischargeable from the discharge aperture 500.
FIG. 2 is a plan view of the above related-art toner supply device in a state in which the shutter member 200 is inserted into the casing 300.
Upon insertion of the shutter member 200 in the casing 300, a pair of arm portions 220 of the shutter member 200 is brought into contact with inner surfaces of the casing 300 while elastically deforming from a shape shown by two-dot chain lines to that shown by solid lines. Since the pair of arm portions 220 is elastically deformable, the shutter member 200 can be easily inserted into the casing 300 without forming a gap between the shutter member 200 and an inner surface of the casing 300. As is not shown in FIG. 2 for the sake of simplicity, a seal member is stretched between the arms 220.
In a case in which the shutter member 200 is exposed to elastic deformation for a long period of time, the deformed portion may cause plastic deformation due to concentration of stress. As a result, the shutter member 200 may not sufficiently seal the casing 300.